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March 11, 2009 -- Low vitamin D levels greatly increase a teenager’s risk of diabetes and heart disease, Johns Hopkins researchers find.
It is becoming clear that adults who get too little vitamin D are at higher risk for diabetes and heart disease. Now, it appears vitamin D levels also affect these risks earlier in life, say Johns Hopkins researchers Jared P. Reis, PhD, and colleagues.
The researchers analyzed data from 3,577 adolescents aged 12 to 19 enrolled in National Health and Nutrition Examination surveys from 2001 through 2004.
Compared to the 25% of teens with the highest levels of vitamin D in their blood (more than 26 nanograms per milliliter), the 25% of teens with the lowest vitamin D levels (less than 15 ng/mL) had:
Black teens averaged about half the vitamin D levels seen in white teens (15.5 ng/mL vs. 28.0 ng/mL).
Although the findings suggest that vitamin D supplements would be helpful, Reis warns that it remains to be proven whether this would reduce diabetes and heart disease risk.
"We believe clinical trials designed to determine the effects of vitamin D supplementation on heart disease risk factors in adolescents should be conducted before recommendations can be made for vitamin D in the prevention of cardiovascular disease," Reis says in a news release.
And supplements may not be the best way to get vitamin D, suggests American Heart Association past president Robert H. Eckel, MD.
"The AHA recommends an overall healthy diet and lifestyle, and that people get their nutrients primarily from food sources rather than supplements," Eckel says in the news release.
How much vitamin D is enough? That's still being debated. The American Academy of Pediatrics recently suggested a daily intake of 400 IU. But some experts say children and teens need more than 1,000 IU of vitamin D every day.
People who are obese are more likely to have vitamin D deficiency than normal-weight people. Reis suggests this may be because vitamin D is fat soluble and gets tucked away in fat tissue.
"We are just now starting to understand the role that vitamin D may play in cardiovascular health," Reis says.
Reis reported the findings at this week's American Heart Association meeting in Palm Harbor, Fla.